There are many applications in which it is required to apply a level of management in respect of wireless communications resources and the management of information, particularly between a moving platform and one or more remote platform(s), and maintain adequate wireless communications therebetween for safe operation of the moving platform and mission success.
For example, in the case of aerial vehicles and, more particularly, unmanned aerial vehicles (UAVs), there is an ongoing and stringent requirement to maintain an adequate communications link between the aerial vehicle and a ground station, for example, and unexpected loss or degradation of such a communication link can be catastrophic.
A UAS is composed of three main parts, the unmanned air vehicle (UAV), unmanned control station (UCS) and support systems of the UAS (for pre-mission planning). A UAS Mission System may be composed of the following functional components/subsystems: Mission Management, Communications, Vehicle Health, Navigation System, Airspace Integration, Payload and Power Management. Multiple, different dynamic in-mission planners may reside in one or more of the above-mentioned functional components/subsystems. In a typical UAV, a dynamic route planner generates a new route, in real time, when there is a change in the operational environment, e.g. severe weather, threat, or a change of circumstances, e.g. an emergency, or a dynamic manoeuvre plan is generated to avoid an airborne obstacle. The aim is thus to maintain safety and the survivability of the aircraft by determining a feasible route and/or manoeuvre in real time, while avoiding pop-up, static and dynamic obstacles, for example.
However, the operational environment of moving platforms, at least in some applications, can be particularly challenging from a communications perspective. The antennas are normally securely mounted to an aircraft and are not movable relative to the aircraft. An antenna on the aircraft used for transmitting messages will not always be optimally oriented with respect to the recipient as the aircraft manoeuvres. The signal is lost or adversely affected by aircraft orientation, which cause the antenna on the aircraft to be pointed in an unfavourable direction or the path between the transmitting antenna on the aircraft and recipient to be blocked by the aircraft structure (e.g. wing). Thus, a particular on-board antenna may not always be optimally oriented to establish or maintain an adequate communications with an antenna on another node, as the aircraft manoeuvres.
An on-board antenna for transmitting messages may be oriented in an unfavourable direction relative to an imposed emissions control (EMCON) region or with respect to an adversary. Also, the energy radiated in that direction may exceed an acceptable threshold for emissions control, increasing the vulnerability of the node and possibly betraying its existence. Traditionally a platform is required to operate in silence, in order to avoid being overheard. If the communications system was able to adapt and respond accordingly, for example by using an alternate antenna, it may still be possible to maintain communications whilst adhering to EMCON.
CHEN-MOU CHENG ET AL, “Transmit Antenna Selection Based on Link-layer Channel Probing”, World of Wireless, Mobile and Multimedia Networks, 2007, IEEE 2007 describes a method of transmit antenna selection for a moving platform by periodically transmitting a probe packet from alternating antennas to the recipient node. The recipient node is configured to receive the probe packets and send back, to the transmitting node, data representative of the received signals strengths so that the transmitting node can select the best antenna for ongoing transmissions. However, this process requires the cooperation (and correct configuration) of the recipient node. The transmitting node (i.e. the moving platform) cannot perform the antenna selection autonomously or, indeed, dynamically based only on the data it wants to send and the recipient node it wishes to transmit to.
It would therefore be desirable to provide an intelligent communications management system for a moving platform that is able to adapt and respond dynamically to an uncertain dynamic battlefield environment, such as threats, by managing their communications resources accordingly.